Implications of Temperature and Prey Density on Predatory Mite Amblyseius swirskii (Acari: Phytoseiidae) Functional Responses

Abstract

<i>Amblyseius swirskii</i> are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. <i>Tetranychus urticae</i> is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on <i>A. swirskii</i>, a biological control agent for <i>T. urticae</i>. The present results demonstrated the change in the functional response estimates when <i>A. swirskii</i> was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency (<i>a'</i>) showed the highest value (<i>a'</i> = 0.919) at 26 °C and the lowest value (<i>a'</i> = 0.751) at 14 °C. The handling time per prey item (<i>T_h</i>) for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C (<i>T_h</i> = 0.005) and the highest value at 14 °C (<i>T_h</i> = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for <i>A. swirskii</i> showed a significant difference between the mean numbers of <i>T. urticae</i> consumed at various prey densities and temperatures, illustrating a relationship between <i>A. swirskii</i> and <i>T. urticae.</i> Therefore, the results of this research may be utilized to forecast the behavior of <i>A. swirskii</i> and its usefulness in controlling <i>T. urticae</i> populations.